Question

Heating ethanol with excess concentrated sulphuric acid gives ______.

• A. butane
• B. ethene
• C. propyne
• D. methane

Answer 1

The correct option is B ethene

In the given situation, concentrated sulphuric acid act as a dehydrating agent.
When ethanol is heated at 443 K with excess concentrated sulphuric acid, it causes its dehydration (loss of water). This results in the formation of ethene.
The reaction occurs as follows:

${\text{CH}}_3{\text{CH}}_2\text{OH}\text{(aq)}\underset{{\text{H}}_2{\text{SO}}_4}{\overset{\text{Hot Conc.}}{\to }}{\text{CH}}_2={\text{CH}}_2\text{(g)}+{\text{H}}_2\text{O(l)}$